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Commit 926973ec authored by Narayan Kamath's avatar Narayan Kamath
Browse files

Replace hand written offsets with structures.

Given that all current & future android ABIs are
little endian, we can get rid of the explicit conversions
from memory regions to little endian data members.

Also cleans up a few C style casts that snuck in during
several -Werror efforts and fixes temporary file generation
on target.

bug: 15448202

Change-Id: I4fcbb3c1124cb82c82139d328344e54fc7895353
parent 30136150
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+253 −156
Original line number Diff line number Diff line
@@ -35,59 +35,173 @@

#include "ziparchive/zip_archive.h"

// This is for windows. If we don't open a file in binary mode, weirds
// This is for windows. If we don't open a file in binary mode, weird
// things will happen.
#ifndef O_BINARY
#define O_BINARY 0
#endif

/*
 * Zip file constants.
 */
static const uint32_t kEOCDSignature     = 0x06054b50;
static const uint32_t kEOCDLen           = 2;
static const uint32_t kEOCDNumEntries    = 8;             // number of entries in the archive
static const uint32_t kEOCDSize          = 12;            // size of the central directory
static const uint32_t kEOCDFileOffset    = 16;            // offset to central directory
static const uint32_t kEOCDCommentLen    = 20;            // length of the EOCD comment
static const uint32_t kEOCDComment       = 22;            // offset of the EOCD comment

static const uint32_t kMaxCommentLen    = 65535;          // longest possible in ushort
static const uint32_t kMaxEOCDSearch    = (kMaxCommentLen + kEOCDLen);

static const uint32_t kLFHSignature     = 0x04034b50;
static const uint32_t kLFHLen           = 30;             // excluding variable-len fields
static const uint32_t kLFHGPBFlags      = 6;              // general purpose bit flags
static const uint32_t kLFHCRC           = 14;             // offset to CRC
static const uint32_t kLFHCompLen       = 18;             // offset to compressed length
static const uint32_t kLFHUncompLen     = 22;             // offset to uncompressed length
static const uint32_t kLFHNameLen       = 26;             // offset to filename length
static const uint32_t kLFHExtraLen      = 28;             // offset to extra length

static const uint32_t kCDESignature     = 0x02014b50;
static const uint32_t kCDELen           = 46;             // excluding variable-len fields
static const uint32_t kCDEMethod        = 10;             // offset to compression method
static const uint32_t kCDEModWhen       = 12;             // offset to modification timestamp
static const uint32_t kCDECRC           = 16;             // offset to entry CRC
static const uint32_t kCDECompLen       = 20;             // offset to compressed length
static const uint32_t kCDEUncompLen     = 24;             // offset to uncompressed length
static const uint32_t kCDENameLen       = 28;             // offset to filename length
static const uint32_t kCDEExtraLen      = 30;             // offset to extra length
static const uint32_t kCDECommentLen    = 32;             // offset to comment length
static const uint32_t kCDELocalOffset   = 42;             // offset to local hdr

static const uint32_t kDDOptSignature   = 0x08074b50;     // *OPTIONAL* data descriptor signature
static const uint32_t kDDSignatureLen   = 4;
static const uint32_t kDDLen            = 12;
static const uint32_t kDDMaxLen         = 16;             // max of 16 bytes with a signature, 12 bytes without
static const uint32_t kDDCrc32          = 0;              // offset to crc32
static const uint32_t kDDCompLen        = 4;              // offset to compressed length
static const uint32_t kDDUncompLen      = 8;              // offset to uncompressed length
#define DISALLOW_IMPLICIT_CONSTRUCTORS(TypeName) \
    TypeName(); \
    TypeName(const TypeName&); \
    void operator=(const TypeName&)

// The "end of central directory" (EOCD) record. Each archive
// contains exactly once such record which appears at the end of
// the archive. It contains archive wide information like the
// number of entries in the archive and the offset to the central
// directory of the offset.
struct EocdRecord {
  static const uint32_t kSignature = 0x06054b50;

  // End of central directory signature, should always be
  // |kSignature|.
  uint32_t eocd_signature;
  // The number of the current "disk", i.e, the "disk" that this
  // central directory is on.
  //
  // This implementation assumes that each archive spans a single
  // disk only. i.e, that disk_num == 1.
  uint16_t disk_num;
  // The disk where the central directory starts.
  //
  // This implementation assumes that each archive spans a single
  // disk only. i.e, that cd_start_disk == 1.
  uint16_t cd_start_disk;
  // The number of central directory records on this disk.
  //
  // This implementation assumes that each archive spans a single
  // disk only. i.e, that num_records_on_disk == num_records.
  uint16_t num_records_on_disk;
  // The total number of central directory records.
  uint16_t num_records;
  // The size of the central directory (in bytes).
  uint32_t cd_size;
  // The offset of the start of the central directory, relative
  // to the start of the file.
  uint32_t cd_start_offset;
  // Length of the central directory comment.
  uint16_t comment_length;
 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(EocdRecord);
} __attribute__((packed));

// A structure representing the fixed length fields for a single
// record in the central directory of the archive. In addition to
// the fixed length fields listed here, each central directory
// record contains a variable length "file_name" and "extra_field"
// whose lengths are given by |file_name_length| and |extra_field_length|
// respectively.
struct CentralDirectoryRecord {
  static const uint32_t kSignature = 0x02014b50;

  // The start of record signature. Must be |kSignature|.
  uint32_t record_signature;
  // Tool version. Ignored by this implementation.
  uint16_t version_made_by;
  // Tool version. Ignored by this implementation.
  uint16_t version_needed;
  // The "general purpose bit flags" for this entry. The only
  // flag value that we currently check for is the "data descriptor"
  // flag.
  uint16_t gpb_flags;
  // The compression method for this entry, one of |kCompressStored|
  // and |kCompressDeflated|.
  uint16_t compression_method;
  // The file modification time and date for this entry.
  uint16_t last_mod_time;
  uint16_t last_mod_date;
  // The CRC-32 checksum for this entry.
  uint32_t crc32;
  // The compressed size (in bytes) of this entry.
  uint32_t compressed_size;
  // The uncompressed size (in bytes) of this entry.
  uint32_t uncompressed_size;
  // The length of the entry file name in bytes. The file name
  // will appear immediately after this record.
  uint16_t file_name_length;
  // The length of the extra field info (in bytes). This data
  // will appear immediately after the entry file name.
  uint16_t extra_field_length;
  // The length of the entry comment (in bytes). This data will
  // appear immediately after the extra field.
  uint16_t comment_length;
  // The start disk for this entry. Ignored by this implementation).
  uint16_t file_start_disk;
  // File attributes. Ignored by this implementation.
  uint16_t internal_file_attributes;
  // File attributes. Ignored by this implementation.
  uint32_t external_file_attributes;
  // The offset to the local file header for this entry, from the
  // beginning of this archive.
  uint32_t local_file_header_offset;
 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(CentralDirectoryRecord);
} __attribute__((packed));

// The local file header for a given entry. This duplicates information
// present in the central directory of the archive. It is an error for
// the information here to be different from the central directory
// information for a given entry.
struct LocalFileHeader {
  static const uint32_t kSignature = 0x04034b50;

  // The local file header signature, must be |kSignature|.
  uint32_t lfh_signature;
  // Tool version. Ignored by this implementation.
  uint16_t version_needed;
  // The "general purpose bit flags" for this entry. The only
  // flag value that we currently check for is the "data descriptor"
  // flag.
  uint16_t gpb_flags;
  // The compression method for this entry, one of |kCompressStored|
  // and |kCompressDeflated|.
  uint16_t compression_method;
  // The file modification time and date for this entry.
  uint16_t last_mod_time;
  uint16_t last_mod_date;
  // The CRC-32 checksum for this entry.
  uint32_t crc32;
  // The compressed size (in bytes) of this entry.
  uint32_t compressed_size;
  // The uncompressed size (in bytes) of this entry.
  uint32_t uncompressed_size;
  // The length of the entry file name in bytes. The file name
  // will appear immediately after this record.
  uint16_t file_name_length;
  // The length of the extra field info (in bytes). This data
  // will appear immediately after the entry file name.
  uint16_t extra_field_length;
 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(LocalFileHeader);
} __attribute__((packed));

struct DataDescriptor {
  // The *optional* data descriptor start signature.
  static const uint32_t kOptSignature = 0x08074b50;

  // CRC-32 checksum of the entry.
  uint32_t crc32;
  // Compressed size of the entry.
  uint32_t compressed_size;
  // Uncompressed size of the entry.
  uint32_t uncompressed_size;
 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(DataDescriptor);
} __attribute__((packed));

#undef DISALLOW_IMPLICIT_CONSTRUCTORS

static const uint32_t kGPBDDFlagMask = 0x0008;         // mask value that signifies that the entry has a DD

static const uint32_t kMaxErrorLen = 1024;

// The maximum size of a central directory or a file
// comment in bytes.
static const uint32_t kMaxCommentLen = 65535;

// The maximum number of bytes to scan backwards for the EOCD start.
static const uint32_t kMaxEOCDSearch = kMaxCommentLen + sizeof(EocdRecord);

static const char* kErrorMessages[] = {
  "Unknown return code.",
  "Iteration ended",
@@ -313,39 +427,21 @@ static int32_t AddToHash(ZipEntryName *hash_table, const uint64_t hash_table_siz
  return 0;
}

/*
 * Get 2 little-endian bytes.
 */
static uint16_t get2LE(const uint8_t* src) {
  return src[0] | (src[1] << 8);
}

/*
 * Get 4 little-endian bytes.
 */
static uint32_t get4LE(const uint8_t* src) {
  uint32_t result;

  result = src[0];
  result |= src[1] << 8;
  result |= src[2] << 16;
  result |= src[3] << 24;

  return result;
}

static int32_t MapCentralDirectory0(int fd, const char* debug_file_name,
                                    ZipArchive* archive, off64_t file_length,
                                    uint32_t read_amount, uint8_t* scan_buffer) {
                                    off64_t read_amount, uint8_t* scan_buffer) {
  const off64_t search_start = file_length - read_amount;

  if (lseek64(fd, search_start, SEEK_SET) != search_start) {
    ALOGW("Zip: seek %" PRId64 " failed: %s", (int64_t)search_start, strerror(errno));
    ALOGW("Zip: seek %" PRId64 " failed: %s", static_cast<int64_t>(search_start),
          strerror(errno));
    return kIoError;
  }
  ssize_t actual = TEMP_FAILURE_RETRY(read(fd, scan_buffer, read_amount));
  if (actual != (ssize_t) read_amount) {
    ALOGW("Zip: read %" PRIu32 " failed: %s", read_amount, strerror(errno));
  ssize_t actual = TEMP_FAILURE_RETRY(
      read(fd, scan_buffer, static_cast<size_t>(read_amount)));
  if (actual != static_cast<ssize_t>(read_amount)) {
    ALOGW("Zip: read %" PRId64 " failed: %s", static_cast<int64_t>(read_amount),
          strerror(errno));
    return kIoError;
  }

@@ -355,9 +451,10 @@ static int32_t MapCentralDirectory0(int fd, const char* debug_file_name,
   * doing an initial minimal read; if we don't find it, retry with a
   * second read as above.)
   */
  int i;
  for (i = read_amount - kEOCDLen; i >= 0; i--) {
    if (scan_buffer[i] == 0x50 && get4LE(&scan_buffer[i]) == kEOCDSignature) {
  int i = read_amount - sizeof(EocdRecord);
  for (; i >= 0; i--) {
    if (scan_buffer[i] == 0x50 &&
        ((*reinterpret_cast<uint32_t*>(&scan_buffer[i])) == EocdRecord::kSignature)) {
      ALOGV("+++ Found EOCD at buf+%d", i);
      break;
    }
@@ -368,44 +465,43 @@ static int32_t MapCentralDirectory0(int fd, const char* debug_file_name,
  }

  const off64_t eocd_offset = search_start + i;
  const uint8_t* eocd_ptr = scan_buffer + i;

  assert(eocd_offset < file_length);

  const EocdRecord* eocd = reinterpret_cast<const EocdRecord*>(scan_buffer + i);
  /*
   * Grab the CD offset and size, and the number of entries in the
   * archive.  Verify that they look reasonable. Widen dir_size and
   * dir_offset to the file offset type.
   * Verify that there's no trailing space at the end of the central directory
   * and its comment.
   */
  const uint16_t num_entries = get2LE(eocd_ptr + kEOCDNumEntries);
  const off64_t dir_size = get4LE(eocd_ptr + kEOCDSize);
  const off64_t dir_offset = get4LE(eocd_ptr + kEOCDFileOffset);
  const uint16_t comment_length = get2LE(eocd_ptr + kEOCDCommentLen);

  if (eocd_offset + comment_length + kEOCDComment != file_length) {
  const off64_t calculated_length = eocd_offset + sizeof(EocdRecord)
      + eocd->comment_length;
  if (calculated_length != file_length) {
    ALOGW("Zip: %" PRId64 " extraneous bytes at the end of the central directory",
          (int64_t) (file_length - (eocd_offset + comment_length + kEOCDComment)));
          static_cast<int64_t>(file_length - calculated_length));
    return kInvalidFile;
  }

  if (dir_offset + dir_size > eocd_offset) {
    ALOGW("Zip: bad offsets (dir %" PRId64 ", size %" PRId64 ", eocd %" PRId64 ")",
        (int64_t)dir_offset, (int64_t)dir_size, (int64_t)eocd_offset);
  /*
   * Grab the CD offset and size, and the number of entries in the
   * archive and verify that they look reasonable.
   */
  if (eocd->cd_start_offset + eocd->cd_size > eocd_offset) {
    ALOGW("Zip: bad offsets (dir %" PRIu32 ", size %" PRIu32 ", eocd %" PRId64 ")",
        eocd->cd_start_offset, eocd->cd_size, static_cast<int64_t>(eocd_offset));
    return kInvalidOffset;
  }
  if (num_entries == 0) {
  if (eocd->num_records == 0) {
    ALOGW("Zip: empty archive?");
    return kEmptyArchive;
  }

  ALOGV("+++ num_entries=%d dir_size=%" PRId64 " dir_offset=%" PRId64,
        num_entries, (int64_t)dir_size, (int64_t)dir_offset);
  ALOGV("+++ num_entries=%" PRIu32 "dir_size=%" PRIu32 " dir_offset=%" PRIu32,
        eocd->num_records, eocd->cd_size, eocd->cd_start_offset);

  /*
   * It all looks good.  Create a mapping for the CD, and set the fields
   * in archive.
   */
  android::FileMap* map = MapFileSegment(fd, dir_offset, dir_size,
  android::FileMap* map = MapFileSegment(fd,
      static_cast<off64_t>(eocd->cd_start_offset),
      static_cast<size_t>(eocd->cd_size),
      true /* read only */, debug_file_name);
  if (map == NULL) {
    archive->directory_map = NULL;
@@ -413,8 +509,8 @@ static int32_t MapCentralDirectory0(int fd, const char* debug_file_name,
  }

  archive->directory_map = map;
  archive->num_entries = num_entries;
  archive->directory_offset = dir_offset;
  archive->num_entries = eocd->num_records;
  archive->directory_offset = eocd->cd_start_offset;

  return 0;
}
@@ -440,12 +536,12 @@ static int32_t MapCentralDirectory(int fd, const char* debug_file_name,
  }

  if (file_length > (off64_t) 0xffffffff) {
    ALOGV("Zip: zip file too long %" PRId64, (int64_t)file_length);
    ALOGV("Zip: zip file too long %" PRId64, static_cast<int64_t>(file_length));
    return kInvalidFile;
  }

  if (file_length < (int64_t) kEOCDLen) {
    ALOGV("Zip: length %" PRId64 " is too small to be zip", (int64_t)file_length);
  if (file_length < static_cast<off64_t>(sizeof(EocdRecord))) {
    ALOGV("Zip: length %" PRId64 " is too small to be zip", static_cast<int64_t>(file_length));
    return kInvalidFile;
  }

@@ -461,12 +557,12 @@ static int32_t MapCentralDirectory(int fd, const char* debug_file_name,
   *
   * We start by pulling in the last part of the file.
   */
  uint32_t read_amount = kMaxEOCDSearch;
  if (file_length < (off64_t) read_amount) {
  off64_t read_amount = kMaxEOCDSearch;
  if (file_length < read_amount) {
    read_amount = file_length;
  }

  uint8_t* scan_buffer = (uint8_t*) malloc(read_amount);
  uint8_t* scan_buffer = reinterpret_cast<uint8_t*>(malloc(read_amount));
  int32_t result = MapCentralDirectory0(fd, debug_file_name, archive,
                                        file_length, read_amount, scan_buffer);

@@ -482,9 +578,9 @@ static int32_t MapCentralDirectory(int fd, const char* debug_file_name,
 */
static int32_t ParseZipArchive(ZipArchive* archive) {
  int32_t result = -1;
  const uint8_t* cd_ptr = (const uint8_t*) archive->directory_map->getDataPtr();
  size_t cd_length = archive->directory_map->getDataLength();
  uint16_t num_entries = archive->num_entries;
  const uint8_t* const cd_ptr = (const uint8_t*) archive->directory_map->getDataPtr();
  const size_t cd_length = archive->directory_map->getDataLength();
  const uint16_t num_entries = archive->num_entries;

  /*
   * Create hash table.  We have a minimum 75% load factor, possibly as
@@ -499,39 +595,43 @@ static int32_t ParseZipArchive(ZipArchive* archive) {
   * Walk through the central directory, adding entries to the hash
   * table and verifying values.
   */
  const uint8_t* const cd_end = cd_ptr + cd_length;
  const uint8_t* ptr = cd_ptr;
  for (uint16_t i = 0; i < num_entries; i++) {
    if (get4LE(ptr) != kCDESignature) {
    const CentralDirectoryRecord* cdr =
        reinterpret_cast<const CentralDirectoryRecord*>(ptr);
    if (cdr->record_signature != CentralDirectoryRecord::kSignature) {
      ALOGW("Zip: missed a central dir sig (at %" PRIu16 ")", i);
      goto bail;
    }

    if (ptr + kCDELen > cd_ptr + cd_length) {
    if (ptr + sizeof(CentralDirectoryRecord) > cd_end) {
      ALOGW("Zip: ran off the end (at %" PRIu16 ")", i);
      goto bail;
    }

    const off64_t local_header_offset = get4LE(ptr + kCDELocalOffset);
    const off64_t local_header_offset = cdr->local_file_header_offset;
    if (local_header_offset >= archive->directory_offset) {
      ALOGW("Zip: bad LFH offset %" PRId64 " at entry %" PRIu16, (int64_t)local_header_offset, i);
      goto bail;
    }

    const uint16_t file_name_length = get2LE(ptr + kCDENameLen);
    const uint16_t extra_length = get2LE(ptr + kCDEExtraLen);
    const uint16_t comment_length = get2LE(ptr + kCDECommentLen);
    const uint16_t file_name_length = cdr->file_name_length;
    const uint16_t extra_length = cdr->extra_field_length;
    const uint16_t comment_length = cdr->comment_length;

    /* add the CDE filename to the hash table */
    const char* file_name = reinterpret_cast<const char *>(ptr + sizeof(CentralDirectoryRecord));
    const int add_result = AddToHash(archive->hash_table,
        archive->hash_table_size, (const char*) ptr + kCDELen, file_name_length);
        archive->hash_table_size, file_name, file_name_length);
    if (add_result) {
      ALOGW("Zip: Error adding entry to hash table %d", add_result);
      result = add_result;
      goto bail;
    }

    ptr += kCDELen + file_name_length + extra_length + comment_length;
    if ((size_t)(ptr - cd_ptr) > cd_length) {
    ptr += sizeof(CentralDirectoryRecord) + file_name_length + extra_length + comment_length;
    if ((ptr - cd_ptr) > static_cast<int64_t>(cd_length)) {
      ALOGW("Zip: bad CD advance (%tu vs %zu) at entry %" PRIu16,
          ptr - cd_ptr, cd_length, i);
      goto bail;
@@ -606,21 +706,19 @@ void CloseArchive(ZipArchiveHandle handle) {

static int32_t UpdateEntryFromDataDescriptor(int fd,
                                             ZipEntry *entry) {
  uint8_t ddBuf[kDDMaxLen];
  uint8_t ddBuf[sizeof(DataDescriptor) + sizeof(DataDescriptor::kOptSignature)];
  ssize_t actual = TEMP_FAILURE_RETRY(read(fd, ddBuf, sizeof(ddBuf)));
  if (actual != sizeof(ddBuf)) {
    return kIoError;
  }

  const uint32_t ddSignature = get4LE(ddBuf);
  uint16_t ddOffset = 0;
  if (ddSignature == kDDOptSignature) {
    ddOffset = 4;
  }
  const uint32_t ddSignature = *(reinterpret_cast<const uint32_t*>(ddBuf));
  const uint16_t offset = (ddSignature == DataDescriptor::kOptSignature) ? 4 : 0;
  const DataDescriptor* descriptor = reinterpret_cast<const DataDescriptor*>(ddBuf + offset);

  entry->crc32 = get4LE(ddBuf + ddOffset + kDDCrc32);
  entry->compressed_length = get4LE(ddBuf + ddOffset + kDDCompLen);
  entry->uncompressed_length = get4LE(ddBuf + ddOffset + kDDUncompLen);
  entry->crc32 = descriptor->crc32;
  entry->compressed_length = descriptor->compressed_size;
  entry->uncompressed_length = descriptor->uncompressed_size;

  return 0;
}
@@ -656,19 +754,22 @@ static int32_t FindEntry(const ZipArchive* archive, const int ent,
  // Recover the start of the central directory entry from the filename
  // pointer.  The filename is the first entry past the fixed-size data,
  // so we can just subtract back from that.
  const unsigned char* ptr = (const unsigned char*) name;
  ptr -= kCDELen;
  const uint8_t* ptr = reinterpret_cast<const uint8_t*>(name);
  ptr -= sizeof(CentralDirectoryRecord);

  // This is the base of our mmapped region, we have to sanity check that
  // the name that's in the hash table is a pointer to a location within
  // this mapped region.
  const unsigned char* base_ptr = (const unsigned char*)
    archive->directory_map->getDataPtr();
  const uint8_t* base_ptr = reinterpret_cast<const uint8_t*>(
    archive->directory_map->getDataPtr());
  if (ptr < base_ptr || ptr > base_ptr + archive->directory_map->getDataLength()) {
    ALOGW("Zip: Invalid entry pointer");
    return kInvalidOffset;
  }

  const CentralDirectoryRecord *cdr =
      reinterpret_cast<const CentralDirectoryRecord*>(ptr);

  // The offset of the start of the central directory in the zipfile.
  // We keep this lying around so that we can sanity check all our lengths
  // and our per-file structures.
@@ -677,22 +778,22 @@ static int32_t FindEntry(const ZipArchive* archive, const int ent,
  // Fill out the compression method, modification time, crc32
  // and other interesting attributes from the central directory. These
  // will later be compared against values from the local file header.
  data->method = get2LE(ptr + kCDEMethod);
  data->mod_time = get4LE(ptr + kCDEModWhen);
  data->crc32 = get4LE(ptr + kCDECRC);
  data->compressed_length = get4LE(ptr + kCDECompLen);
  data->uncompressed_length = get4LE(ptr + kCDEUncompLen);
  data->method = cdr->compression_method;
  data->mod_time = cdr->last_mod_time;
  data->crc32 = cdr->crc32;
  data->compressed_length = cdr->compressed_size;
  data->uncompressed_length = cdr->uncompressed_size;

  // Figure out the local header offset from the central directory. The
  // actual file data will begin after the local header and the name /
  // extra comments.
  const off64_t local_header_offset = get4LE(ptr + kCDELocalOffset);
  if (local_header_offset + (off64_t) kLFHLen >= cd_offset) {
  const off64_t local_header_offset = cdr->local_file_header_offset;
  if (local_header_offset + static_cast<off64_t>(sizeof(LocalFileHeader)) >= cd_offset) {
    ALOGW("Zip: bad local hdr offset in zip");
    return kInvalidOffset;
  }

  uint8_t lfh_buf[kLFHLen];
  uint8_t lfh_buf[sizeof(LocalFileHeader)];
  ssize_t actual = ReadAtOffset(archive->fd, lfh_buf, sizeof(lfh_buf),
                                 local_header_offset);
  if (actual != sizeof(lfh_buf)) {
@@ -700,30 +801,25 @@ static int32_t FindEntry(const ZipArchive* archive, const int ent,
    return kIoError;
  }

  if (get4LE(lfh_buf) != kLFHSignature) {
  const LocalFileHeader *lfh = reinterpret_cast<const LocalFileHeader*>(lfh_buf);

  if (lfh->lfh_signature != LocalFileHeader::kSignature) {
    ALOGW("Zip: didn't find signature at start of lfh, offset=%" PRId64,
        (int64_t)local_header_offset);
        static_cast<int64_t>(local_header_offset));
    return kInvalidOffset;
  }

  // Paranoia: Match the values specified in the local file header
  // to those specified in the central directory.
  const uint16_t lfhGpbFlags = get2LE(lfh_buf + kLFHGPBFlags);
  const uint16_t lfhNameLen = get2LE(lfh_buf + kLFHNameLen);
  const uint16_t lfhExtraLen = get2LE(lfh_buf + kLFHExtraLen);

  if ((lfhGpbFlags & kGPBDDFlagMask) == 0) {
    const uint32_t lfhCrc = get4LE(lfh_buf + kLFHCRC);
    const uint32_t lfhCompLen = get4LE(lfh_buf + kLFHCompLen);
    const uint32_t lfhUncompLen = get4LE(lfh_buf + kLFHUncompLen);

  if ((lfh->gpb_flags & kGPBDDFlagMask) == 0) {
    data->has_data_descriptor = 0;
    if (data->compressed_length != lfhCompLen || data->uncompressed_length != lfhUncompLen
        || data->crc32 != lfhCrc) {
    if (data->compressed_length != lfh->compressed_size
        || data->uncompressed_length != lfh->uncompressed_size
        || data->crc32 != lfh->crc32) {
      ALOGW("Zip: size/crc32 mismatch. expected {%" PRIu32 ", %" PRIu32
        ", %" PRIx32 "}, was {%" PRIu32 ", %" PRIu32 ", %" PRIx32 "}",
        data->compressed_length, data->uncompressed_length, data->crc32,
        lfhCompLen, lfhUncompLen, lfhCrc);
        lfh->compressed_size, lfh->uncompressed_size, lfh->crc32);
      return kInconsistentInformation;
    }
  } else {
@@ -732,9 +828,9 @@ static int32_t FindEntry(const ZipArchive* archive, const int ent,

  // Check that the local file header name matches the declared
  // name in the central directory.
  if (lfhNameLen == nameLen) {
    const off64_t name_offset = local_header_offset + kLFHLen;
    if (name_offset + lfhNameLen >= cd_offset) {
  if (lfh->file_name_length == nameLen) {
    const off64_t name_offset = local_header_offset + sizeof(LocalFileHeader);
    if (name_offset + lfh->file_name_length >= cd_offset) {
      ALOGW("Zip: Invalid declared length");
      return kInvalidOffset;
    }
@@ -760,7 +856,8 @@ static int32_t FindEntry(const ZipArchive* archive, const int ent,
    return kInconsistentInformation;
  }

  const off64_t data_offset = local_header_offset + kLFHLen + lfhNameLen + lfhExtraLen;
  const off64_t data_offset = local_header_offset + sizeof(LocalFileHeader)
      + lfh->file_name_length + lfh->extra_field_length;
  if (data_offset > cd_offset) {
    ALOGW("Zip: bad data offset %" PRId64 " in zip", (int64_t)data_offset);
    return kInvalidOffset;
+19 −4

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